Process for the reproduction of the recorded displacements or vibrations of a mediumsuch as air



Oct. 27, 1925. D I 1,558,734

W. A. LOTH PROCESS FOR THE REPRODUCTION OF THE RECORDED DISPLACEMENTS OR VIBRATIONS OF A MEDIUM SUCH AS AIR Filed Jan. 5, 1922 2 Sheets-Sheet l I luv (2 nit/011 H v14. L 0 17 MM Oct. 27, 1925. 1,558,734

W. A. LOTH PROCESS FOR THE REPRODUCTION OF THE RECORDED DISPLACEMENTS 0R VIBRATIONS OF A MEDIUM SUCH AS AIR Filed Jan. 5, 1922 2 Sheets-Sheet 2 2 Ire/v @IZEOL hffllo up,

An a.

Patented Oct. 27, 1925.

UNITED STATES,

PATENT OFFICE.

WILLIAM ARTHUR LO'IH, or rams, rmon, ASSIGNOR 'ro scorers mnosrmmn DES rnocnnns w. A. LO'IH, or PARIS, FRANCE. I

PROCESS FOR THE REPBODUGTION OI THE RECORDED DIS PLACEMENTS OR .01 AMEDIUM SUCH AIR.

Application filed January 3, 1822. Serial Ito. 526,834.

To all who-m. it may concern:

Be it known that I, WILLIAM An'rHUR LOTH, citizen of the French Republic, re-

' siding at 130 Rue Lecourbe, Paris, France,

graphically construed in the form of a'line;

this line represents graphically the composition of the sinusoidal functions, of variable amplitudes, corresponding to each fundamental sound and to its harmonics.

This process is essentially characterized in that use is made for analyzing the film (which is divided by the line in two sur- ,faces, of different thicknesses) a series of exploring styluses the points of contact of which with the film are arranged accordin to a parallel relatively to the ordinates o the figurative line. These styluses are so hinged that the displacements to which they are subjected, owing to their application on the impressed surface of the film, determine the corresponding displacements either of a diaphragm or of a lamella respectively depending from each of the exploring styluses and the whole of which plays the part of a diaphragm relatively to a stethoscopic chamber, the displacements of this diaphragm determining the vibrations of the air for the reproduction of the recorded sounds.

In the accompanying diagrammatic drawing, givenby way of example,

Fig. 1 illustrates, in plan view, a form of carrying out the process forming the subject-matter of the invention.

Fig. 2. is a corresponding side view thereof on an enlarged scale.

Fig. 3 is a perspective view of the arrangement shown in Figs. 1 and 2.-

Figs. 4 and 5 are Ian and side views respectively of a modi cations Fig. 6 is a cross section of a special recorded film adapted to be used with the means of phonic reproduction of Figs. 1 to 4, with the modification indicated hereafter.

For carrying out the process forming the subject matter of the invention the .sur-

faces of the film serving as an intermediary and separated by the recorded line or tracing to be repr uced, enlarged or-not, have relatively to each other a constant or variable relief in a direction at right angles to minimum the width of thesaid film; For instance,

the film 1 has a constant relief in all the hatched surface 2 limited b the recorded line or tracing 3. This can e obtained by using either a film made of any material, metallic or not, corrugated or not, or a film coated with bichromated gelatin, for instance. Instead of obtaining a surface in relief, it is obvious, that an intaglio surface can be employed.

For the reproduction, the thus made passes under a number of exploring needles .4, having blunt or very fine points, arranged parallel to each other on a common support 5 extending transversely to the direction of unwinding of the said film 1 (Fig. 2).

The needles 4 can rock about the axis 5 arranged transversely to the film 1. The needles control, through rods 6, having the same or different lengths, according to the mode of action adopted, an axis 7 having a groove in which the ends of the rods are engaged. This axis 7 is pivoted at one of its ends 8, whilst its other end 9 fits or is' connected to a reproduction diaphragm 10 surmounted by a reinforcing acoustical mouth-piece 11.

The operation is as follows:

Supposing the film 1 presents a surface having a constant relief 2 limited by the recorded line or tracing 3 and that it moves in the direction of the arrow 00, each needle 4 coming in contact with the relief surface 2 will be lifted. But, considering that the axis 7 pivoted about its end 8, is engaged at different points by the rods 6 which resenting the recorded vibrations will determine displacements of the diaphragm 10 which will exactly reproduce the said vibrations. Each needle 42 is lifted only if it comes in engagement with a relief and this lifting imparts to the reproducing diaphragm 10, a displacement equal to that to which has been subjected the corresponding diaphragm during the recording operatlon.

In themodification illustrated in Flg. 6,

the film 1 is not provided with an impressed surface, having a constant relief, but the thickness of this surface increases from one of the edgestowards the other. For the inclination thus realized, that is to say for the relative heights of the relief at different points, the same conditions as these lIldlcated above are to be applied concern ng the mode of construction of the exploring needles 4.

- In the device shown in Figs. 4 and 5, the diaphragm 10 is constituted by the uxtaposition of resilient lamellae 10 respectively actuated by the corresponding needles. These lamellae 1O aremounted on felt bands or strips 12 which permit their displacement and fit on the edge of a stethoscopic cavity 13, for instance. The needles 4 are pivoted on a common axis of rotation 5'wl1ich is inclined relatively to the width of the film 1, in the case of a film having'an increasing relief as indicated in Fig. 6.

Each lifting of a needle 4 varies the inner volume of the chamber 13 which communicates, through acoustical pipes, withlistening devices or is provided with an ear. piece 11. I

The variations of volume of the chamber 13 correspond therefore to the line or tracing 3 carried by the film 1 but, in order that the reproduction may be exact, it is convenient that the displacements to which are subjected the volume of air may have an amplitude proportional to that of the vibrations represented by the graphic tracing carried by the film 1. For that purpose, use is made of a surface having variable reliefs; this surface, as already stated, can be increasing from the edge limiting the film to the figurative tracing 3 on the latter (Fig. 6). By realizing this condition and varying the lever arms actuating the needles 4, the vibrations of the volume of air contained in .and the lamellae 10 constituting the diaphragm and closing the chamber 13, levers which amplify, by observing the rule indicated, the displacements of the said needles at and thelengths of which increase from the edge of the film 1 to the analytic line or tracing 3 carried by the latter.

For verifying the exactness of the reproduction, a mirror can be mounted on the receiving diaphragm and, by means of a luminous bundle, the spot is projected and its tracing 1s compared with the standard trac-' What I claim as my invention and desire to secure by Letters Patent is:

1. In the installation for the reproduction of movements to which a medium such as air is subjected, a movable surface on which the diagrammatic tracing showing the movements divides the said surface into parts of relativelydiiferent heights-the projecting part havmg a progressively decreasing helght from one "to the other edge of the surface, needles whose ends engage with the parts of the movable surface, an axis arranged transversely to said movable Surface, a reproducing diaphragm, and means to transmit the movements of the needles to the reproducing diaphragm.

2. In the installation for the reproduction of movements to' which a medium such as air is subjected, a movable surface on which the diagrammatic tracing showing the movements divides the said surface into parts of relatively difl'erent heights, the projecting part having a progressively decreasing height from one to the other edge of the surface, parallel needles whose ends engage with the parts of the movable surface, an

axis arranged transverselyto said movable surface, rods extending the needles beyond their pivot point on the common axis, a reproducing diaphragm, and an intermediate axis arranged transversely with respect to the film, pivoted at one of its ends and the other end acting on the reproducing diaphragm. I

3. In the installation for the reproduction of movements to which a medium such as air 7 is subjected, a movable surface on'which the diagrammatic tracing showing the movements divides the said surface into parts of relatively different heights, the projecting part having a progressively decreasing height from one to the other edge of the surface, parallel needles whose ends engage with the parts of the movable surface, an

axis arranged transversely to said movable surface, rods extending the needles beyond their pivot point on the cominon axis, a reproducing diaphragm, and an intermediate axis arranged transversely with. respect to the film, pivoted at one of its ends and the other end eating on the reproducing diaphragm and also provided with a longitudinal groove in which is engaged the outer ends of the needle rods.

In testimony whereof I have aflixed my signature. I

WILLIAM ARTHUR 

